The present invention deals primarily with compound archery bows, generally including a bow frame and a cable system on the frame mounted to at least two rotational elements such as wheels. Early compound bow wheels or cams were basically a round wheel with the axle hole located off center to produce let-off as the bow is pulled to full draw. These eccentrically mounted wheels have a mass center off-set from the axle hole. When rotated about an axle, the inertia of the off-center mass produces a kick which causes the rest of the system to gyrate. This causes a kick or vibration/shock movement which is imparted to the bow and archer when the bow is shot. This kick can disrupt the archer's aim or the archer absorbs this energy as opposed to the energy being transferred to the arrow or the arrow's flight.
As bow efficiencies increased and the need for higher performance and velocities were required, the off-center mass kick of eccentric mass cams was amplified. One response to this vibration/shock was to use a sacrificial dampening device. One of the first devices designed was a forward stabilizer, which mounted on the front portion of the riser. When the bow was shot, a portion of the excess vibration was absorbed by the stabilizer. As time evolved, other types of dampening systems were designed including devices that were mounted in the riser for the purpose of absorbing vibration. These dampening systems do not absorb all of the vibration.
Another method of dissipating the overall bow kick was the use of a perimeter weight in the cam to offset limb kick. Since the limbs travel in a forward direction when shot, there was a forward movement and inertia imparted to the bow, away from the archer. By mounting a weight on the outside perimeter of the cam, in a fashion that moved in the opposite direction of the limb as the bow was shot, the effects of the limb movement were partially counteracted or cancelled.
Another effort to cancel the bow's kick or forward movement was found in the geometry of the bow. By orienting the limbs in such a way that the limb tip movement was closer to vertical movement, it was discovered that some of the forward limb kick was eliminated. When the bow is pulled to full draw, the limbs were pulled towards each other as opposed to moving towards the archer. When the bowstring was released, the limb tips would move in a near vertical direction. By creating this opposing movement, the limbs and cams somewhat cancelled each other, creating a more pleasurable shooting bow. Nevertheless, even when the perimeter weighted cam and vertical limb technology were used together, the bow still typically had a kick.
An improved bow and cam are desired.